NASA senior research scientist Robert Nelson, shown Sept. 29 outside the NASA Jet Propulsion Lab in Pasadena, Calif., is party to a suit against the US government challenging background checks of JPL workers. The US Supreme Court heard arguments in the case Oct. 5.

Washington — The lawyer for a group of top scientists at NASA’s Jet Propulsion Laboratory in California encountered a skeptical bench on Tuesday as he urged the US Supreme Court to declare that open-ended government background investigations violate his clients’ right to privacy.

Pasadena lawyer Dan Stormer told the high court that government contractors like his clients, who perform “low-risk” work, should not have to face intrusive questioning about drug treatment or counseling simply to qualify for a government-issued ID badge.

At issue in the case is whether the government violates the JPL workers’ constitutional right to informational privacy when they are told that they must agree to answer all the government’s questions or lose their jobs.

The process also authorized investigators to ask neighbors and others for adverse information about violations of the law, financial integrity, drug or alcohol abuse, mental or emotional stability, general behavior, or other matters.

A group of 28 scientists, engineers, and administrators at the Jet Propulsion Laboratory filed a lawsuit against the National Aeronautics and Space Administration charging that the agency’s new background investigation requirements violated their constitutional right to keep certain intimate details of their lives free from government scrutiny.

A federal judge threw the case out, but the Ninth US Circuit Court of Appeals reversed. The appeals court granted a preliminary injunction, blocking the background checks pending the outcome of the case.

At the Supreme Court on Tuesday, Acting Solicitor General Neal Katyal told the justices that background checks are a standard way of doing business. “These checks have been going on for millions of employees,” he said.

Federal civil service employees have faced background checks since 1953. The checks were expanded to federal contractors in 2005.

The Jet Propulsion Laboratory is run by employees of the California Institute of Technology. Although it is a NASA facility, its workers aren’t federal employees, but rather are contractors.

Scientists describe JPL as a campus-like environment. No one is performing classified or top secret research. And while there are armed guards at the entrance, there had been no background check requirement since JPL opened in 1958. Many of the suing scientists have been working successfully at JPL for 20 years or more and object to the sudden intrusion into their private lives.

Mr. Stormer said the Constitution prevents the government from eliciting intimate details of someone’s life unless it can first demonstrate a legitimate state interest justifying the intrusion. Even then, he said, any intrusion must be narrowly tailored.

Mr. Katyal said the government could meet that standard, if required, but that it would cause significant problems. “This is a roadmap for anyone to come in and say, ‘This question isn’t suitable for me,’ “ Katyal said.

He added that such protests would create a “practical burden for the government.”

In the past five years, Katyal said, 74,000 contractors have undergone background investigations. He said adverse information obtained in the investigative process disqualified 128 of them. None was disqualified for revealing he or she had engaged in drug treatment, he said. In each case, the information remained private between the individual and the government, he said.

Stormer said applying the background checks to scientists at JPL is overkill. He said it was a badge procedure for low-risk employees in a campus-like atmosphere.

Katyal disputed this. He said the research at JPL is scientifically sensitive and that a JPL badge could gain its holder access to every NASA facility, including a position six to 10 feet from the space shuttle prior to launch.

In the most significant attack on Stormer’s position, Justice Scalia questioned the existence of a constitutional right to informational privacy. “I just don’t see it anywhere in the Constitution,” he said.

Stormer answered that it resided in the Fifth Amendment’s protection of life, liberty, and property. “It is the liberty to control information about one’s self without governmental intrusion,” he said.

The session included some questions friendly to Stormer’s position. Justice Sonia Sotomayor asked whether the government was free to ask anything it wanted in a background investigation. For example, could investigators seek to determine an individual’s genetic makeup to try to prevent hiring employees who might be more likely to be diagnosed with cancer? she asked.

Chief Justice John Roberts asked whether citizens retain any right to tell the government in response to an inquiry that “It is none of your business.”

Katyal said the government is free to collect intimate personal information when it is acting as an employer or proprietor so long as the intimate information is not disclosed. “The government is simply mirroring what private employers do,” he said.

Scalia suggested that Congress could place limits on government background investigations if the investigations became too intrusive.

The acting solicitor general said the federal Privacy Act prevents the unauthorized disclosure of intimate personal information by the federal government.

Only eight of the nine justices participated in the oral argument session. The court’s newest justice, Elena Kagan, agreed not to participate in the case because she had worked on it during her recent tenure as solicitor general.

A decision in the case, NASA v. Nelson, is expected later in the term.